Meagan Otten and Alvin Phanh

GPS devices are used by people for driving, walking and mountaineering, and navigation at sea.


  • Only two satellites are needed
  • Circles Intersect
  • Can be rough and inaccurate


  • Needs 3 satellites
  • Except instead of circles intersecting, spheres or cones intersect
  • More accurate

How a GPS Works:

GPS systems work using GPS Receivers, the devices which carry or mount in their vehicles and a network of GPS Satellites.

GPS Receivers use trilateration to calculate their position on Earth. Each GPS receiver has a catalog of satellites and their current positions. As the receiver detects radio waves from a satellite, it calculates the time taken for the signal to reach it. This enables the receiver to know how far it is from the satellite and, therefore, how far it is from a known position in space.

Social and Ethical Considerations:

  • Privacy
  • Surveillance
  • Security
  • Reliability


  • Can be stolen (Hardware)
  • Someone can put a tracker on your vehicle\
  • Can take you to the wrong place
  • Out dated information


  • Pets: microchip
  • Elderly, Alzheimer's: shoes
  • Kids/Teenagers: backpacks & cell phones
  • Prisoners, Parolees

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